gnucash unstable: Fix CXX Flags for g++.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/44fc5b05 (commit)
	from  https://github.com/Gnucash/gnucash/commit/bbd2df6a (commit)



commit 44fc5b0555dd6cbc21b304a3aa68fe1335278208
Author: John Ralls <jralls at ceridwen.us>
Date:   Tue Dec 26 18:23:09 2017 -0800

    Fix CXX Flags for g++.



Summary of changes:
 CMakeLists.txt                  |  4 ++--
 common/test-core/CMakeLists.txt | 12 ++++++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)